Underground service grounded conductors shall be insulated except ___.

• A. When used in a raceway
• B. No exceptions
• C. Bare copper grounded conductor is approved for all soil conditions
• D. In direct sunlight

Answer: (A)

Underground service conductors face moisture, soil chemicals, and physical hazards, so insulation protects the grounded conductor from moisture and damage. The only time that insulation isn’t required is when the grounded conductor is placed in a raceway; the raceway itself provides the necessary moisture and mechanical protection, making additional insulation unnecessary for the conductor inside. Outside of that raceway scenario, insulation is required. Bare conductors in soil aren’t generally approved, and the option about direct sunlight doesn’t apply to underground installations.